Adding upstream version 6.8.upstream/6.8upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 489 insertions, 0 deletions

diff --git a/man/man2/ioctl_fat.2 b/man/man2/ioctl_fat.2
new file mode 100644
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+++ b/man/man2/ioctl_fat.2
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+.\" Copyright (C) 2014, Heinrich Schuchardt <xypron.glpk@gmx.de>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.TH ioctl_fat 2 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+ioctl_fat \- manipulating the FAT filesystem
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.BR "#include <linux/msdos_fs.h>" "     /* Definition of [" V ] FAT_* " and"
+.BR "                                   ATTR_* " constants */"
+.B #include <sys/ioctl.h>
+.P
+.BI "int ioctl(int " fd ", FAT_IOCTL_GET_ATTRIBUTES, uint32_t *" attr );
+.BI "int ioctl(int " fd ", FAT_IOCTL_SET_ATTRIBUTES, uint32_t *" attr );
+.BI "int ioctl(int " fd ", FAT_IOCTL_GET_VOLUME_ID, uint32_t *" id );
+.BI "int ioctl(int " fd ", VFAT_IOCTL_READDIR_BOTH,"
+.BI "          struct __fat_dirent " entry [2]);
+.BI "int ioctl(int " fd ", VFAT_IOCTL_READDIR_SHORT,"
+.BI "          struct __fat_dirent " entry [2]);
+.fi
+.SH DESCRIPTION
+The
+.BR ioctl (2)
+system call can be used to read and write metadata of FAT filesystems that
+are not accessible using other system calls.
+.SS Reading and setting file attributes
+Files and directories in the FAT filesystem possess an attribute bit mask that
+can be read with
+.B FAT_IOCTL_GET_ATTRIBUTES
+and written with
+.BR FAT_IOCTL_SET_ATTRIBUTES .
+.P
+The
+.I fd
+argument contains a file descriptor for a file or directory.
+It is sufficient to create the file descriptor by calling
+.BR open (2)
+with the
+.B O_RDONLY
+flag.
+.P
+The
+.I attr
+argument contains a pointer to a bit mask.
+The bits of the bit mask are:
+.TP
+.B ATTR_RO
+This bit specifies that the file or directory is read-only.
+.TP
+.B ATTR_HIDDEN
+This bit specifies that the file or directory is hidden.
+.TP
+.B ATTR_SYS
+This bit specifies that the file is a system file.
+.TP
+.B ATTR_VOLUME
+This bit specifies that the file is a volume label.
+This attribute is read-only.
+.TP
+.B ATTR_DIR
+This bit specifies that this is a directory.
+This attribute is read-only.
+.TP
+.B ATTR_ARCH
+This bit indicates that this file or directory should be archived.
+It is set when a file is created or modified.
+It is reset by an archiving system.
+.P
+The zero value
+.B ATTR_NONE
+can be used to indicate that no attribute bit is set.
+.SS Reading the volume ID
+FAT filesystems are identified by a volume ID.
+The volume ID can be read with
+.BR FAT_IOCTL_GET_VOLUME_ID .
+.P
+The
+.I fd
+argument can be a file descriptor for any file or directory of the
+filesystem.
+It is sufficient to create the file descriptor by calling
+.BR open (2)
+with the
+.B O_RDONLY
+flag.
+.P
+The
+.I id
+argument is a pointer to the field that will be filled with the volume ID.
+Typically the volume ID is displayed to the user as a group of two
+16-bit fields:
+.P
+.in +4n
+.EX
+printf("Volume ID %04x\-%04x\en", id >> 16, id & 0xFFFF);
+.EE
+.in
+.SS Reading short filenames of a directory
+A file or directory on a FAT filesystem always has a short filename
+consisting of up to 8 capital letters, optionally followed by a period
+and up to 3 capital letters for the file extension.
+If the actual filename does not fit into this scheme, it is stored
+as a long filename of up to 255 UTF-16 characters.
+.P
+The short filenames in a directory can be read with
+.BR VFAT_IOCTL_READDIR_SHORT .
+.B VFAT_IOCTL_READDIR_BOTH
+reads both the short and the long filenames.
+.P
+The
+.I fd
+argument must be a file descriptor for a directory.
+It is sufficient to create the file descriptor by calling
+.BR open (2)
+with the
+.B O_RDONLY
+flag.
+The file descriptor can be used only once to iterate over the directory
+entries by calling
+.BR ioctl (2)
+repeatedly.
+.P
+The
+.I entry
+argument is a two-element array of the following structures:
+.P
+.in +4n
+.EX
+struct __fat_dirent {
+    long            d_ino;
+    __kernel_off_t  d_off;
+    uint32_t short  d_reclen;
+    char            d_name[256];
+};
+.EE
+.in
+.P
+The first entry in the array is for the short filename.
+The second entry is for the long filename.
+.P
+The
+.I d_ino
+and
+.I d_off
+fields are filled only for long filenames.
+The
+.I d_ino
+field holds the inode number of the directory.
+The
+.I d_off
+field holds the offset of the file entry in the directory.
+As these values are not available for short filenames, the user code should
+simply ignore them.
+.P
+The field
+.I d_reclen
+contains the length of the filename in the field
+.IR d_name .
+To keep backward compatibility, a length of 0 for the short filename signals
+that the end of the directory has been reached.
+However, the preferred method for detecting the end of the directory
+is to test the
+.BR ioctl (2)
+return value.
+If no long filename exists, field
+.I d_reclen
+is set to 0 and
+.I d_name
+is a character string of length 0 for the long filename.
+.SH RETURN VALUE
+On error, \-1 is returned, and
+.I errno
+is set to indicate the error.
+.P
+For
+.B VFAT_IOCTL_READDIR_BOTH
+and
+.B VFAT_IOCTL_READDIR_SHORT
+a return value of 1 signals that a new directory entry has been read and
+a return value of 0 signals that the end of the directory has been reached.
+.SH ERRORS
+.TP
+.B ENOENT
+This error is returned by
+.B VFAT_IOCTL_READDIR_BOTH
+and
+.B VFAT_IOCTL_READDIR_SHORT
+if the file descriptor
+.I fd
+refers to a removed, but still open directory.
+.TP
+.B ENOTDIR
+This error is returned by
+.B VFAT_IOCTL_READDIR_BOTH
+and
+.B VFAT_IOCTL_READDIR_SHORT
+if the file descriptor
+.I fd
+does not refer to a directory.
+.TP
+.B ENOTTY
+The file descriptor
+.I fd
+does not refer to an object in a FAT filesystem.
+.P
+For further error values, see
+.BR ioctl (2).
+.SH STANDARDS
+Linux.
+.SH HISTORY
+.TP
+.B VFAT_IOCTL_READDIR_BOTH
+.TQ
+.B VFAT_IOCTL_READDIR_SHORT
+Linux 2.0.
+.TP
+.B FAT_IOCTL_GET_ATTRIBUTES
+.TQ
+.B FAT_IOCTL_SET_ATTRIBUTES
+.\" just before we got Git history
+Linux 2.6.12.
+.TP
+.B FAT_IOCTL_GET_VOLUME_ID
+Linux 3.11.
+.\" commit 6e5b93ee55d401f1619092fb675b57c28c9ed7ec
+.SH EXAMPLES
+.SS Toggling the archive flag
+The following program demonstrates the usage of
+.BR ioctl (2)
+to manipulate file attributes.
+The program reads and displays the archive attribute of a file.
+After inverting the value of the attribute,
+the program reads and displays the attribute again.
+.P
+The following was recorded when applying the program for the file
+.IR /mnt/user/foo :
+.P
+.in +4n
+.EX
+# ./toggle_fat_archive_flag /mnt/user/foo
+Archive flag is set
+Toggling archive flag
+Archive flag is not set
+.EE
+.in
+.SS Program source (toggle_fat_archive_flag.c)
+\&
+.\" SRC BEGIN (toggle_fat_archive_flag.c)
+.EX
+#include <fcntl.h>
+#include <linux/msdos_fs.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+\&
+/*
+ * Read file attributes of a file on a FAT filesystem.
+ * Output the state of the archive flag.
+ */
+static uint32_t
+readattr(int fd)
+{
+    int       ret;
+    uint32_t  attr;
+\&
+    ret = ioctl(fd, FAT_IOCTL_GET_ATTRIBUTES, &attr);
+    if (ret == \-1) {
+        perror("ioctl");
+        exit(EXIT_FAILURE);
+    }
+\&
+    if (attr & ATTR_ARCH)
+        printf("Archive flag is set\en");
+    else
+        printf("Archive flag is not set\en");
+\&
+    return attr;
+}
+\&
+int
+main(int argc, char *argv[])
+{
+    int       fd;
+    int       ret;
+    uint32_t  attr;
+\&
+    if (argc != 2) {
+        printf("Usage: %s FILENAME\en", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+\&
+    fd = open(argv[1], O_RDONLY);
+    if (fd == \-1) {
+        perror("open");
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Read and display the FAT file attributes.
+     */
+    attr = readattr(fd);
+\&
+    /*
+     * Invert archive attribute.
+     */
+    printf("Toggling archive flag\en");
+    attr \[ha]= ATTR_ARCH;
+\&
+    /*
+     * Write the changed FAT file attributes.
+     */
+    ret = ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
+    if (ret == \-1) {
+        perror("ioctl");
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Read and display the FAT file attributes.
+     */
+    readattr(fd);
+\&
+    close(fd);
+\&
+    exit(EXIT_SUCCESS);
+}
+.EE
+.\" SRC END
+.SS Reading the volume ID
+The following program demonstrates the use of
+.BR ioctl (2)
+to display the volume ID of a FAT filesystem.
+.P
+The following output was recorded when applying the program for
+directory
+.IR /mnt/user :
+.P
+.in +4n
+.EX
+$ ./display_fat_volume_id /mnt/user
+Volume ID 6443\-6241
+.EE
+.in
+.SS Program source (display_fat_volume_id.c)
+\&
+.\" SRC BEGIN (display_fat_volume_id.c)
+.EX
+#include <fcntl.h>
+#include <linux/msdos_fs.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+\&
+int
+main(int argc, char *argv[])
+{
+    int       fd;
+    int       ret;
+    uint32_t  id;
+\&
+    if (argc != 2) {
+        printf("Usage: %s FILENAME\en", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+\&
+    fd = open(argv[1], O_RDONLY);
+    if (fd == \-1) {
+        perror("open");
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Read volume ID.
+     */
+    ret = ioctl(fd, FAT_IOCTL_GET_VOLUME_ID, &id);
+    if (ret == \-1) {
+        perror("ioctl");
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Format the output as two groups of 16 bits each.
+     */
+    printf("Volume ID %04x\-%04x\en", id >> 16, id & 0xFFFF);
+\&
+    close(fd);
+\&
+    exit(EXIT_SUCCESS);
+}
+.EE
+.\" SRC END
+.SS Listing a directory
+The following program demonstrates the use of
+.BR ioctl (2)
+to list a directory.
+.P
+The following was recorded when applying the program to the directory
+.IR /mnt/user :
+.P
+.in +4n
+.EX
+$ \fB./fat_dir /mnt/user\fP
+\&. \-> \[aq]\[aq]
+\&.. \-> \[aq]\[aq]
+ALONGF\[ti]1.TXT \-> \[aq]a long filename.txt\[aq]
+UPPER.TXT \-> \[aq]\[aq]
+LOWER.TXT \-> \[aq]lower.txt\[aq]
+.EE
+.in
+.\"
+.SS Program source
+.in +4n
+.\" SRC BEGIN (ioctl_fat.c)
+.EX
+#include <fcntl.h>
+#include <linux/msdos_fs.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+\&
+int
+main(int argc, char *argv[])
+{
+    int                  fd;
+    int                  ret;
+    struct __fat_dirent  entry[2];
+\&
+    if (argc != 2) {
+        printf("Usage: %s DIRECTORY\en", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Open file descriptor for the directory.
+     */
+    fd = open(argv[1], O_RDONLY | O_DIRECTORY);
+    if (fd == \-1) {
+        perror("open");
+        exit(EXIT_FAILURE);
+    }
+\&
+    for (;;) {
+\&
+        /*
+         * Read next directory entry.
+         */
+        ret = ioctl(fd, VFAT_IOCTL_READDIR_BOTH, entry);
+\&
+        /*
+         * If an error occurs, the return value is \-1.
+         * If the end of the directory list has been reached,
+         * the return value is 0.
+         * For backward compatibility the end of the directory
+         * list is also signaled by d_reclen == 0.
+         */
+        if (ret < 1)
+            break;
+\&
+        /*
+         * Write both the short name and the long name.
+         */
+        printf("%s \-> \[aq]%s\[aq]\en", entry[0].d_name, entry[1].d_name);
+    }
+\&
+    if (ret == \-1) {
+        perror("VFAT_IOCTL_READDIR_BOTH");
+        exit(EXIT_FAILURE);
+    }
+\&
+    /*
+     * Close the file descriptor.
+     */
+    close(fd);
+\&
+    exit(EXIT_SUCCESS);
+}
+.EE
+.\" SRC END
+.in
+.SH SEE ALSO
+.BR ioctl (2)